24 October 2026
Reference: CVE-2026-111497
1. What is being reported?
Researchers have discovered a critical bug in certain versions of the Brotli decoder, a tool that helps compress and decompress data. This bug can be exploited remotely by attackers sending specially crafted compressed data, potentially leading to system crashes or allowing hackers to run harmful code.
2. What this means in plain English
If your business uses software that includes the affected Brotli versions, attackers might exploit this flaw to disrupt your services, access sensitive information, or gain control over your systems. This could lead to data loss, downtime, or other serious problems.
3. Could this affect a small business?
Small businesses and organisations using software built on Linux, Node.js, Python, or other platforms that include Brotli versions 1.0.3 through 1.2.0 could be at risk. If you do not use software that relies on Brotli compression, or your software supplier has already updated it, you are less likely to be affected.
4. What to do now
- Check with your IT provider or software supplier whether your systems use Brotli compression libraries between versions 1.0.3 and 1.2.0.
- Ensure that any affected Brotli libraries or software are updated to the latest safe versions: 1.0.10, 1.1.1, or 1.2.1 as soon as possible.
- If you use third-party software that might include Brotli, ask the supplier about updates or patches addressing this vulnerability.
- Monitor your systems for unusual activity and maintain regular backups in case of disruption.
5. Ask your IT provider
Can you confirm if any of our systems use Brotli compression libraries between versions 1.0.3 and 1.2.0, and have they been updated to safe versions to protect against the recent critical vulnerability CVE-2026-111497?
6. Bottom line
Update Brotli-related software promptly to prevent hackers from exploiting this serious flaw.
Information based on NVD, CISA KEV, and reputable security news reporting.